$.fn.IsEmpty = function() {
    return ( this.val().trim().length == 0 );
}

$.fn.IsEmptyParagraprh = function() {
}

$.fn.IsValidSelection = function() {
    return ( (this.val() == null) || (this.val() == 'seleccionar') || (this.val() == 'blanco') ? false : true );
}

$.fn.ClearControl = function() {
    var t = this.prop('type');

    if( (t == 'text') || (t == 'textarea') || (t == 'password') ) {
        this.val('');
    } else if( t == 'select-one' ) {
        $( 'option', this ).first().prop( 'selected', true );
    }
}